C#JIRA工作日志更新错误"远程服务器返回错误:(401)未经授权."

我将通过c#应用程序上的JIRA REST API更新JIRA中的问题的工作日志.以下代码显示了我到目前为止所做的工作.

HttpWebResponse返回此错误"远程服务器返回错误:(401)未经授权." .

我尝试使用相同的凭据并在PHP cURL函数中使用相同的数据,它工作正常,并成功更新工作日志.

这是我的Jason转换序列化对象:{"update":{"worklog":[{"add":{"comment":"IJ的示例测试评论","timeSpent":"210"}}}}}

protected string RunQuery(JiraResource resource, string argument = null, string data = null, string method = "PUT")
{
// Where;
// resource = issue
// argument = "JIRA-16"
// Data = {"update":{"worklog":[{"add":{"comment":"Sample test comment by IJ","timeSpent":"210"}}]}}
// Method = "PUT"

        string url = string.Format("{0}{1}/", m_BaseUrl, resource.ToString());

        if (argument != null)
        {
            url = string.Format("{0}{1}", url, argument);
        }

// URL = https://companyname.atlassian.net/rest/api/2/issue/JIRA-16

        HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
        request.ContentType = "application/json";
        request.Method = method;
        request.ContentLength = data.Length;

        using (StreamWriter writer = new StreamWriter(request.GetRequestStream()))
        {
            writer.Write(data);
        }

        string base64Credentials = GetEncodedCredentials(); // check below
        request.Headers.Add("Authorization", "Basic " + base64Credentials);

        HttpWebResponse response = request.GetResponse() as HttpWebResponse;// here returns the error
//The remote server returned an error: (401) Unauthorized.

        string result = string.Empty;
        using (StreamReader reader = new StreamReader(response.GetResponseStream()))
        {
            result = reader.ReadToEnd();
        }

        return result;
}

private string GetEncodedCredentials()
{
        string mergedCredentials = string.Format("{0}:{1}", m_Username, m_Password);
        byte[] byteCredentials = UTF8Encoding.UTF8.GetBytes(mergedCredentials);
        return Convert.ToBase64String(byteCredentials);
}

我哪里做错了？请帮我.